The contents described below merely provide the background information relating to the embodiments of the present invention, and do not constitute the conventional technology.
With respect to low-noise amplifiers (LNA) in a mobile TV tuner environment using ISDB-T (ultra-high frequency band (UHF Band): 470 MHz to 770 MHz)/ISDB-Tmm (Very high frequency (VHF Band): 170 MHz˜280 MHz)/ISDB-Tsb (Low VHF: 90 MHz to 110 MHz)/CATV (Wide-Band: 90 MHz to 810 MHz), high linearity is required to minimize the performance degradation of harmonic mixing due to frequency of 700 MHz to 2.4 GHz used under 3G or 4G and local oscillator (LO).
Conventional low-noise amplifiers (LNA) have employed technology of attenuating Jammer frequency with RF-Filter. First of all, although it is the most effective, the noise figure (NF) of the low-noise amplifier deteriorates, because the technology of using a filter at the input of low-noise amplifier (LNA) has an effect of reducing the power of jammer at the stage of input. Although there also exists a technology of adding a filter between the output of the low-noise amplifier (LNA) and the input of the mixer to avoid the deterioration of the noise figure, integration of chips from modules has become difficult since more external LCs are needed. For the method of using a filter, removal of LTE power at 700 MHz to 800 MHz has become very difficult. As the most difficult example, in case of channel of 707 MHz, removing LTE jammer power of 725 MHz by a filter has become very difficult because their frequencies are close. For instance, interference between TV channels has also become a problem. The performance of a portion where interference generates is improved as the linearity of the low-noise amplifier (LNA) becomes better. Furthermore, each of the low-noise amplifiers (LNA) used in ISDB-T/ISDB-Tmm/ISDB-Tsb/CATV needs a mixer, and there exists a problem of increasing in size due to the structure of the mixer becoming more complex.